First generation TANS (Tactical air navigation system) used Decca and Dopplar for its information. The presentation was a lot more pleasing to the eye then reading 3 clocks and cross refering to a chart from hell, but the accuracy therin remained the same until the advent of GPS. (Which the RNS252 a TANS descendent now employs)
Using the TANS in Central America where Decca was not available was a bummer, but it did sharpen up your time and distance calcs, as skill somewhat lost these days.